Differences in Nitric Oxide Metabolism in Sickle Cell Patients

A study has shown that differing rates of metabolism of nitric oxide, which triggers dilation of blood vessels, may determine why sickle cell anemia affects adult males more seriously than females. The study was published December 23, 2002, in the online edition of Circulation.

Investigators from the National Institutes of Health (Bethesda, MD, USA) studied 21 African-Americans (11 men and 10 women, ages 18 to 55) with sickle cell disease and 18 African-Americans without sickle cell disease. They measured forearm blood flow before and after administering a series of drugs known to affect vessel dilation and blood flow.

According to first author Dr. Mark Gladwin, a clinician-researcher at NIH, "These studies had a surprising result. The men appear to have problems both in making nitric oxide and with increased destruction of nitric oxide. When the men were given a substance containing nitric oxide, their blood flow increased by 86%, while women's blood flow increased 171%.”

The new findings provide a molecular foundation for previous clinical studies that had shown that men with sickle cell disease experienced more sickle cell crises after puberty than do women, and that the median age of death was 42 for men compared to 48 for women.



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